Some studies found that young maternal age explain the negative outcomes but others found that these outcomes are more attributable to socioeconomic background than the maternal age per se. Furthermore, Most studies found in the databases are from the US and the UK, there are few literature based on New Zealand data. Therefore, This project aims to investigate any potential differences on health, wellbeing and development of children born to teenage mothers and those born to older mothers in New Zealand in the first two years of life and how much of these differences attributable to maternal age. The study will use the Growing Up in New Zealand data to answer the research questions.